According to Microsoft’s Service Agreement, if a user don’t log/sign in into his/her email account within “a minimum of every 270 days,” then Microsoft may cancel his/her account and delete their data permanently from its server. And if the company does so, users have nothing to say. However, Microsoft has discovered that many of its users’ Hotmail (now outlook.com) accounts are remained unused. So Microsoft wants to reactivate those inactivated email accounts.
Microsoft has mentioned that when the account becomes inactive, “the email account is automatically queued for deletion from our servers. Then, after a total of 360 days, the email account name is made available again.” But Microsoft hasn’t mentioned the possibility that email account names will be recycled.
Source: PC World